In the past, insertion of tubes into holes in tube plates and middle plates of heat exchangers were assisted mainly by human labor.
The time-honered procedure of tube insertion is therefore low in efficiency and demands a great deal of labor and time especially when thousands of tubes of a few meters long are to be inserted. An automated tube insertion machine has been suggested, for example, in Japanese patent publication No. 16582/1977. Since within the proposed machine the tubes are not conveyed thereto till a tube pusher makes a complete reciprocating movement and the pusher is driven in an interrupted manner, the machine still lacks sufficient efficiency while being more quick to insert the tubes than human labor.
The machine has another problem that, while being guided by way of guide rollers on a support, the tubes are sometimes bent upward out of the guide rollers due to repelling force occurring when any of the tubes is engaged with the holes in the heat exchangers for any reason. Such a problem results in a substantial economic loss in the case where the tubes are made of titanium steel.